Steelmaking, and Steels, Getting Better and Better all the Time
While steel was accidentally discovered by iron craftsmen around 200 BC, it wasn’t until 1740 when a British clockmaker named Benjamin Huntsman stumbled onto a process for producing small batches of what he called crucible steel. This material was only slightly stronger than iron, however. Next came the development of wrought iron, made by the reheating of cast iron. But, what was really needed at the time—primarily for construction and armor—was a stronger iron alloy.
In 1854, looking for a to make a stronger steel needed for the manufacture of a new type of gun barrel he had patented, the famed British inventor Henry Bessemer went to work and, within a few years, perfected his Bessemer blast furnace, ushering in the modern steelmaking industry.
Jump ahead to today where automotive designers work with a large palette of steels so that they can match a unique steel type to each application in the vehicle. As Ron Krupitzer, vice president, automotive applications at the American Iron and Steel Institute (AISI), puts it, “Due to evolving requirements from automobiles in terms of safety and fuel economy, steel needs to reinvent itself on a regular basis in order to survive competition from other materials.”
I spoke recently with Krupitzer and with Roger Heimbuch, executive director of the Auto/Steel Partnership, about what their groups are heralding as the third generation of advanced high-strength steels (AHSS). The article in this issue covers primarily first-generation AHSS. Second-generation AHSS, say Krupitzer and Heimbuch, just now being introduced by European and Japanese steelmakers, offer impressive properties, but are expensive to manufacture. Needed are affordable new AHSS types with properties that fall between first- and second-generation types.
“Our computer design models show that when we remove the restraints on steel properties, the ideal steels for passenger cars require an improvement in properties (strength and elongation) of about 20 percent compared to first-gen. AHSS,” says Heimbuch.
As a result, the National Science Foundation currently is funding (along with the U.S. Department of Energy, AISI and the Auto/Steel Partnership) research that will lead to the development of the third-generation AHSS that Krupitzer and Heimbuch describe. Leading researchers at eight U.S. universities recently received grants totaling $1 million per year for three years. “They will perform research on the metallurgical approaches needed to get the microstructures and properties that, so far, we have not had in automotive steels,” says Krupitzer.
“The R & D process starts from the user perspective—the automakers telling the steelmakers what’s needed from new steels,” adds Heimbuch. “The chance is pretty good, therefore, that we should see results from our three-year research program transfer into production within 5 to 10 years.”
If only Bessemer had any inclination what his invention would lead to.
Want to learn more about the new steels and how they are being applied in today’s automobiles? Plan now to attend the AISI Great Designs in Steel seminar, April 9, 2008, in Livonia, MI. Call 248/945-4769 for information; www.autosteel.org.
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